Process of making laminated glass



July 11, 1944- L. DIKESLAR PROCESS OF MAKING LAMINATED GLASS Filed Nov. 5, 1940 2 Sheets-Sheet l awe Wm L. D. A ESL HR,

July 11, 1944. L. D. KEsLAR PROCESS OF MAKING LAMINATED GLASS 2 Sheets-Sheet 2 Filed Nov. 5,.1940

' 3110mm LD; K5525? amount of fleidbility therein.

tiered by plastic material which is to Patented July 11, 1944 uui rr.

2,353,673 PROCESS Q1? ATED GLASS lLeroy D. llieslar,

Pittsburgh Plate Tarcntusm, Pa, asslgnor to (Glass @ompariy, Allegheny County, Pa... a (corporation oi Pennsylvania Application Noveinher 5, 1946), Serial No. 36%,437

1 Claim.

' The present invention relates to safety glass and more particularly to laminated glass in which the reinforcing plastic interlayer extends beyond the covering glass plates to form a border therefor, and to the processes of manufacture of such glass.

An object of the present invention is topro vide a laminated safety glass having a border of plastic material projecting therefrom.

Other objects and advantages of the invention will be more apparent from the following detailed description of certain preferred einhodi ments thereof.

Safety glass comprising a plurality oi glass plates bonded together into a interposed layers of plastic material is well known. The recent trend of streamlining, however, has raised several new problems of positioning safety glass in order that it will lie substantially flush with the surface 01 the vehicle being glazed. Where the plate of safety glass is mounted in a frame, which in turn is secured to the supporting structure, it will at once be obvious that there will be a projection extend-- his beyond the surface of the vehicle or the glass panel will he recessed in the surface. in either event, the air stream passing over the glazed portion of a vehicle will be disturbed and will re suit in an increased air resistance and accompanying loss of efdciency.

Another problem which confronts the engineers and designers arises from the desireto improve on rigid structures and to provide a certain When the glass laminae are supported in a frame, flexing or movement of the supporting structure places an undue strain upon the glass, with the result considerable breakage of the glass is eizperi enced.

Briefly stated, the present invention cohtein plates the formation of a laminated hor he posi tioned in a supporting structure through the plastic harder. In this manner, the laminated unit will "float in the vehicle walls and the possibility of breakage of the glass thereof will be materially reduced.

In the drawing, Figure l is a plan vier. oi a lasted unit constructed in accordance with the provisions of my invention.

Figure 2 is a vertical sectional view thereof;

Figure 3 is a vertical sectional view oi other form. oi? the invent. on;

Figures i and 5 are fragmentary sectional views composite unit by.

oi multiplate laminate glass at an intermediate stage of manufacture;

Figure 6 is a vertical sectional view of a com pleted multiplate laminated glass. Fig. 'l' is a fragmentary cross section or an assembly of lam mated unit, frames and bag in a heating chamber; Fig. 8 is a fragmentary plan oi a bag adapteel to contain the assembled unit; and Fig. 9 is a fragmentary cross section of a multiple plate laminated unit with frames and bag applied thereto. I

Referring to Figures 1 and 2 of the drawing, a laminated unit 5 comprises glass plates ii acihered centrally on the opposite sides of a sheet 3 of plastic material of larger dimension than the glass plates and in such manner that a horder 5 of the plastic material is formed around the pcrimeters of the glass plates. The inter-layer sheet 3 of plastic material is of greater thiclrness than. that ordinarily used in the preparation. of safety glass and the glass plates may he said to be embedded therein for the plastic ma terlal envelopes the edges of the glass plates. According to Fig. 2 the border 5 is so formed that it decreases in thickness outwardly from the edges of the glass plates.

In the form of the invention illustrated in Figure 3, the plastic interlayer sheet ll forms a horder 65 around the edges of the glass plates 2, and has continuous shoulders 71 extending at right angles to opposite sides of the glass and in con tact with the edges of the glass plates.

As shown in Figures 4, 5 and 6, it is possible to apply the principles of my invention tiplate laminated glass. A pluralitg' 4 plates ill are united by intermediate plastic material which extend beyond the of the plates iii to form lips it. The spaces be tween the lips it are filled by strips it of glas tic and the several term a border it (Figure it) around the "one loly. The border ill may he supplied by t dition of strips or lolocks it (Figure 5 of p stic to the assembly of glass plates ill iriternic diate layers ll of plastic.

In positioning the laminated units in vehi cle, suitable securing means, such as bolts. are passed through the plastic borders or" the ra l-ates at spaced intervals and iastened to the vehicle frame. It is intended that the glass laminae he kept free from metallic contact to reduce any possibility of strains or local stresses therein. Thus the plastic borders 5, El, l2-l23 and it in effect constitute flexible mounting houses which are adapted to be clamped tightly for supporting parts of extended plastic "the unit without imposing strains or stresses upon of the plastic material are masked by a nonadhesive substance 20, as for example, a sheet of Cellophane, or other inert masking material, and the assembly is placed ina rubber bag 2|. Suitable closure elements 23 and 24 are included with the bag to confine the laminated unit therein. The bag is evacuated through a conduit 25 and subjected to heat and pressure sufficient to bond the separate elements of the assembly into a composite unit. It is during the heating and pressing operation that the plastic border (Fig. 2) assumes its tapered form.

A laminated unit as illustrated in Figure '3 is obtained by placing molding frames 26 around the assembled plates and plastic in which the projecting areas of the plastic material are masked, before the assembly is subjected to heat and pressure. The molding frames, assembled by bolting the elements thereof together, as indi-.

cated at 21, are larger than the glass plates and are spaced slightly outwardly therefrom, in order that during the laminating operation the plastic material will flow into the edges and frames and space between the glass form the shoulders 1.

.Heat and pressure are applied to the assembly of laminated unit, frames, and bag in a chamber 28, in which the'heat and pressure are controlled in a conventional manner through conduits 29 and 30 that are included in'the .walls of the chamber.

The plastic bordered plate may also be prepared by assembling a plura ty of glass plates and interposed plastic sheets of larger dimensions and filling the spaces between the projecting lips of plastic with strips of plastic. Heat and pressure are then applied to the assembly to bond the several-elements-thereof into a composite unit. The laminating operation welds the several layers of plastic lying to th outside of the glass laminae into a uniform mass forming the desired border for the laminated plate.

Consideration has beengiven to the fact that difliculties will be experienced in assembling multiplate units and aligning properly the glass able thickness and width about the assembly.

Subsequent lamination under heat and pressure will not only unite the glass and plastic interlayers but will also join the plastic strips to the interlayers to form an integral projecting border.

Manifestly it is necessary that the plastic material forming the interlayer of the laminated glass besusceptibleto sure are applied thereto. At the same time too much plasticity will weaken the final structure. The vinyl acetal resins and particularly vinyl butyral are preferred. At the same time, however, the acrylate I resins and other thermoplastic resins ordinarily used-in safety glass may be employed if desired. It is also possible to use a composite interlayer wherein a central stratum of a hard resin is covered with softer thermo- 7 plastic materials. This type of interlayer will insure greater strength in the projecting borders of the unit. The lamination operation follows the standard practices so well known that it is not considered necessary to set them forth in great detail. Obviously the pressure and temperature to which the assembled units are subjected will vary with the types of plastic materials utilized.

It will at once be obvious that various modifications in the types of materials employed and their arrangement are possible without departing from the spirit of the invention or the scope of th appended claim.

What I claim is: A process of manufacturing safety glass which comprises assembling a plurality of glass plates and interposed sheets of plastic material of larger dimensions, masking the exposed areas of the plastic material, applying molding frames to each side of the assembly in spaced relationto the edges of the glass plates, placing the assembly in a rubber bag, evacuating the bag and subjecting the assembly to controlled heat and pressure to bond the separate elements thereof into a composite unit.

. LEROY KESLAR.

flow when heat and pres- 

